Troubleshooting your first few firings

Hi, I have just finished construcing my Rocket Mass heater, along the same lines as the Bonnie. One of Ernie and Erica's builds. It is a 7 inch CSA and the SS insulated chimney is 2 feet above the ridge line.
I know the stove is still wet, but I am having an issue with the flame traveling up the sticks. I have a good draw on the chimney, so I know that is not the issue. Can anyone help me with possible troubleshooting.

Kate; It need to dry before it really starts to draw, there could be other issues like pitchy or stringy wood , but mine did the same thing when wet. I used a small fan that I hand held over the feed tube for a few minutes when it decided it wanted to back draft. Took at least 3 weeks of daily long burns before it started burning properly.

thomas rubino wrote:Kate; It need to dry before it really starts to draw, there could be other issues like pitchy or stringy wood , but mine did the same thing when wet. I used a small fan that I hand held over the feed tube for a few minutes when it decided it wanted to back draft. Took at least 3 weeks of daily long burns before it started burning properly.

Well, it's easier to put a fan at the other end, on the chimney. So you don't have to tend it all the time. I have recuperated a refrigerator fan, and mounted that permanently on the end of the chimney. When i want to startup in windy conditions etc, i just turn it on. And i have noticed, the heat reaches the last metallic elbow far faster. It also burns hotter i think. So both of thoses effects could be beneficial to mass drying.

Kate D.: Try using a brick on top of the Feed Tube to DECREASE The size of the Feed Tubes opening!
This will more directly channel the air flow down past the channels between the wood pieces and promote the
burning of the wood at the tips in the bottom of the Burn tunnel !

Also make sure that you do not have a build-up of wood pieces and hot glowing embers within the Burn tunnel.

The only thing that should be burning in there are the pyrolysed wood gases !

With the air flow directed only at the burning wood you can then add an additional amount of air from a fan !

Also check to make sure all your clean outs are All tight ! and burn the driest wood fine split so there is more
raw wood exposed than bark !

With these simple tips and time I am sure that thomas rubino is right, and it will only be a matter of time, right
now it seems you are burning a lot of wood ! When everything finally dries out the amount of wood you use will
magically shrink

For the Good of the Crafts ! Big AL

thank you all for your speedy response. I am currently burning, dry cedar pieces, no bark. I am gong to get some hard wood over the next couple of days. Closing off part of the feed tube with a brick does really help, and to be honest I am only putting in a few sticks, I have not filled the burn tube, as I am just getting use to the stove.
When it dries out more, and I get some hard wood, I will let you know how she preforms.
Thank you again.

I would like to thank those that responded to my inquiry.......it would appear that the main is the hard wood.. As soon as hard wood is used instead of soft all of my issues disappear. My current situation is finishing the bench. I am not sure whether to put on a lime wash, or what to do. Does anyone have any suggestions?